scholarly journals Linking Atmospheric River Hydrological Impacts on the U.S. West Coast to Rossby Wave Breaking

2017 ◽  
Vol 30 (9) ◽  
pp. 3381-3399 ◽  
Author(s):  
Huancui Hu ◽  
Francina Dominguez ◽  
Zhuo Wang ◽  
David A. Lavers ◽  
Gan Zhang ◽  
...  
Keyword(s):  
United States ◽  
Water Vapor ◽  
Rossby Wave ◽  
West Coast ◽  
Wave Breaking ◽  
The United States ◽  
Rossby Wave Breaking ◽  
Southwest Coast ◽  
Local Topography ◽  
The U.S

Atmospheric rivers (ARs) have significant hydrometeorological impacts on the U.S. West Coast. This study presents the connection between the characteristics of large-scale Rossby wave breaking (RWB) over the eastern North Pacific and the regional-scale hydrological impacts associated with landfalling ARs on the U.S. West Coast (36°–49°N). ARs associated with RWB account for two-thirds of the landfalling AR events and >70% of total AR-precipitation in the winter season. The two regimes of RWB—anticyclonic wave breaking (AWB) and cyclonic wave breaking (CWB)—are associated with different directions of the vertically integrated water vapor transport (IVT). AWB-ARs impinge in a more westerly direction on the coast whereas CWB-ARs impinge in a more southwesterly direction. Most of the landfalling ARs along the northwestern coast of the United States (states of Washington and Oregon) are AWB-ARs. Because of their westerly impinging angles when compared to CWB-ARs, AWB-ARs arrive more orthogonally to the western Cascades and more efficiently transform water vapor into precipitation through orographic lift than CWB-ARs. Consequently, AWB-ARs are associated with the most extreme streamflows in the region. Along the southwest coast of the United States (California), the southwesterly impinging angles of CWB-ARs are more orthogonal to the local topography. Furthermore, the southwest coast CWB-ARs have more intense IVT. Consequently, CWB-ARs are associated with the most intense precipitation. As a result, most of the extreme streamflows in southwest coastal basins are associated with CWB-ARs. In summary, depending on the associated RWB type, ARs impinge on the local topography at a different angle and have a different spatial signature of precipitation and streamflow.

The Ethical Neutrality of Prospective Payments: Justice Issues

1996 ◽  
Vol 5 (4) ◽  
pp. 570-578
Author(s):  
Jean McDowell
Keyword(s):  
United States ◽  
Healthcare System ◽  
West Coast ◽  
Healthcare Delivery ◽  
The United States ◽  
Fee For Service ◽  
Reimbursement Mechanisms ◽  
The West ◽  
The Past ◽  
The U.S

The U.S. healthcare system has been subject to unprecedented scrutiny over the past three years; one of the results of this scrutiny has been recognition of the serious problems that exist in both healthcare delivery and reimbursement mechanisms. While the verbal debate in Washington has essentially ceased, within the healthcare community a historic shift has taken place in the way healthcare reimbursement is structured: increasingly, traditional fee-for-service reimbursement methods are being replaced with capitation reimbursement methods. While this phenomenon originated on the West Coast, it has spread to all geographic sectors of the United States in varying degrees and can be expected to dominate the funding patterns of healthcare over the next decade.

Impact of Rossby Wave Breaking on U.S. West Coast Winter Precipitation during ENSO Events

2013 ◽  
Vol 26 (17) ◽  
pp. 6360-6382 ◽  
Author(s):  
Ju-Mee Ryoo ◽  
Yohai Kaspi ◽  
Darryn W. Waugh ◽  
George N. Kiladis ◽  
Duane E. Waliser ◽  
...  
Keyword(s):  
United States ◽  
West Coast ◽  
El Niño ◽  
Wave Breaking ◽  
El Nino ◽  
The United States ◽  
La Niña ◽  
The West ◽  
La Nina ◽  
Subtropical Jet

Abstract This study demonstrates that water vapor transport and precipitation are largely modulated by the intensity of the subtropical jet, transient eddies, and the location of wave breaking events during the different phases of ENSO. Clear differences are found in the potential vorticity (PV), meteorological fields, and trajectory pathways between the two different phases. Rossby wave breaking events have cyclonic and anticyclonic regimes, with associated differences in the frequency of occurrence and the dynamic response. During La Niña, there is a relatively weak subtropical jet allowing PV to intrude into lower latitudes over the western United States. This induces a large amount of moisture transport inland ahead of the PV intrusions, as well as northward transport to the west of a surface anticyclone. During El Niño, the subtropical jet is relatively strong and is associated with an enhanced cyclonic wave breaking. This is accompanied by a time-mean surface cyclone, which brings zonal moisture transport to the western United States. In both (El Niño and La Niña) phases, there is a high correlation (>0.3–0.7) between upper-level PV at 250 hPa and precipitation over the west coast of the United States with a time lag of 0–1 days. Vertically integrated water vapor fluxes during El Niño are up to 70 kg m−1 s−1 larger than those during La Niña along the west coast of the United States. The zonal and meridional moist static energy flux resembles wave vapor transport patterns, suggesting that they are closely controlled by the large-scale flows and location of wave breaking events during the different phase of ENSO.

scholarly journals Dynamics of Landfalling Atmospheric Rivers over the North Pacific in 30 Years of MERRA Reanalysis

2014 ◽  
Vol 27 (18) ◽  
pp. 7133-7150 ◽  
Author(s):  
Ashley E. Payne ◽  
Gudrun Magnusdottir
Keyword(s):  
Rossby Wave ◽  
West Coast ◽  
Wave Breaking ◽  
Moisture Transport ◽  
Large Scale ◽  
Eastern Pacific ◽  
The West ◽  
Atmospheric Rivers ◽  
Rossby Wave Breaking ◽  
Upper Level

Abstract A large-scale analysis of landfalling atmospheric rivers (ARs) along the west coast of North America and their association with the upper-tropospheric flow is performed for the extended winter (November–March) for the years 1979–2011 using Modern-Era Retrospective Analysis for Research and Applications (MERRA) reanalysis data. The climatology, relationship to the El Niño–Southern Oscillation and the Madden–Julian oscillation, and upper-level characteristics of approximately 750 landfalling ARs are presented based on the 85th percentile of peak daily moisture flux. AR occurrence along the West Coast is dominated by early season events. In composites of upper-level fields during AR occurrences, certain characteristics stand out irrespective of the tropical climate indices. This suggests that extratropical dynamical processes play a key role in AR dynamics. The influence of the large-scale circulation on AR intensity prior to landfall is examined by objectively selecting an extreme subset of 112 landfalling AR dates representing the 95th percentile of strongest cases. Each landfalling AR date that is identified is traced backward in time using a novel semiautomated tracking algorithm based on spatially and temporally connected organized features in integrated moisture transport. Composites of dynamical fields following the eastward progression of ARs show a close relationship of the location of the jet, Rossby wave propagation, and anticyclonic Rossby wave breaking in the upper troposphere of the eastern Pacific and moisture transport in the lower troposphere. Comparison between the strongest and the weakest ARs within the most extreme subset shows differences in both the intensity of moisture transport and the scale and development of anticyclonic Rossby wave breaking in the eastern Pacific.

scholarly journals Trajectory analysis on the origin of air mass and moisture associated with Atmospheric Rivers over the west coast of the United States

2011 ◽  
Vol 11 (4) ◽  
pp. 11109-11142 ◽  
Author(s):  
J.-M. Ryoo ◽  
D. E. Waliser ◽  
E. J. Fetzer
Keyword(s):  
United States ◽  
Water Vapor ◽  
West Coast ◽  
Moisture Transport ◽  
The United States ◽  
Transport Processes ◽  
The West ◽  
Atmospheric Rivers ◽  
Air Masses ◽  
Trajectory Model

Abstract. The origins and pathways of air masses leading to heavy rainfall over the west coast of the United States are examined by computing the back-trajectories in a Lagrangian quasi-isentropic trajectory model. Extreme precipitation over the west coast of the United States often coincides with transport in a deep and narrow corridor of concentrated water vapor band from the ocean, commonly referred to as Atmospheric Rivers (ARs). They also occur in conjunction with moisture plumes emanating from the tropics, or along the mid-latitude storm track. However, the actual moisture sources and the dynamic and thermodynamic processes of the moisture transport, are still unclear. Trajectories are found to be insensitive to the reanalysis data set used; we examined NCEP, GMAO MERRA, and ECMWF ERA-Interim. Reconstructed water vapor mixing ratios along trajectories are in generally good agreement among the reanalysis datasets in most of the subtropics and extratropics, indicating that the large-scale circulation is a primary control for moisture transport over those regions. Clustering and pdf (probability density function) analyses illustrate that trajectories over the west coast of United States have different origins. One group of trajectories (cluster 1) originates in the warm part of extratropical cyclones in the low level. The other group of trajectories (cluster 2) originates in the cold and dry regions in the mid-level (pressures less than 600 hPa) over northeastern Asia, then cross the Pacific Ocean. This study demonstrates that the quasi-isentropic Lagrangian trajectory model and clustering analysis (that have been typically used to analyze trajectories in the upper troposphere and higher altitudes) can be used to examine sources of air masses and moisture, and also associated transport processes in the lower troposphere.

Characteristics of long-duration heavy precipitation events along the West Coast of the United States

2021 ◽  
Author(s):  
Benjamin J. Moore ◽  
Allen B. White ◽  
Daniel J. Gottas
Keyword(s):  
Rossby Wave ◽  
West Coast ◽  
Bering Sea ◽  
North Pacific ◽  
Wave Breaking ◽  
Heavy Precipitation ◽  
The West ◽  
Rossby Wave Breaking ◽  
Long Duration ◽  
Precipitation Events

AbstractProlonged periods (e.g., several days or more) of heavy precipitation can result in sustained high-impact flooding. Herein, an investigation of long-duration heavy precipitation events (HPEs), defined as periods comprising ≥ 3 days with precipitation exceeding the climatological 95th percentile, is conducted for 1979–2019 for the U.S. West Coast, specifically Northern California. An objective flow-based categorization method is applied to identify principal large-scale flow patterns for the events. Four categories are identified and examined through composite analyses and case studies. Two of the categories are characterized by a strong zonal jet stream over the eastern North Pacific, while the other two are characterized by atmospheric blocking over the central North Pacific and the Bering Sea–Alaska region, respectively. The composites and case studies demonstrate that the flow patterns for the HPEs tend to remain in place for several days, maintaining strong baroclinicity and promoting occurrences of multiple cyclones in rapid succession near the West Coast. The successive cyclones result in persistent water vapor flux and forcing for ascent over Northern California, sustaining heavy precipitation. For the zonal jet patterns, cyclones affecting the West Coast tend to occur in the poleward jet exit region in association with cyclonic Rossby wave breaking. For the blocking patterns, cyclones tend to occur in association with anticyclonic Rossby wave breaking on the downstream flank of the block. For Bering Sea–Alaska blocking cases, cyclones can move into this region in conjunction with cyclonically breaking waves that extend into the eastern North Pacific from the upstream flank of the block.

scholarly journals Linkages between Extreme Precipitation Events in the Central and Eastern United States and Rossby Wave Breaking

2019 ◽  
Vol 147 (9) ◽  
pp. 3327-3349 ◽  
Author(s):  
Benjamin J. Moore ◽  
Daniel Keyser ◽  
Lance F. Bosart
Keyword(s):  
United States ◽  
Rossby Wave ◽  
Wave Breaking ◽  
Wave Pattern ◽  
Eastern United States ◽  
Synoptic Scale ◽  
Rossby Wave Breaking ◽  
Extreme Precipitation Events ◽  
Upper Level ◽  
Precipitation Events

AbstractLinkages between extreme precipitation events (EPEs) in the central and eastern United States and synoptic-scale Rossby wave breaking are investigated using 1979–2015 climatologies of EPEs and upper-level potential vorticity (PV) streamers. The investigation focuses on two domains over the central and eastern United States, respectively, and emphasizes widespread EPEs, events exhibiting exceptionally large precipitation volumes. The relative frequency of PV streamers is found to be significantly enhanced relative to climatology immediately upstream of each domain during widespread EPEs. Majorities of the widespread EPEs in the central (~79%) and eastern (~56%) U.S. domains co-occur with a PV streamer positioned immediately upstream. Odds ratios of EPEs for days when a PV streamer occurs upstream of each domain indicate a strong, statistically significant association between EPEs and Rossby wave breaking. The strength of the EPE–Rossby wave breaking linkage, as measured by co-occurrence fractions and odds ratios, tends to increase with increasing EPE precipitation volume, such that the strongest linkage exists for widespread EPEs. Composite analyses reveal that Rossby wave breaking can result in widespread EPEs by establishing a persistent high-amplitude synoptic-scale wave pattern, within which strong poleward water vapor transport and ascent are forced over the EPE region immediately downstream of an elongated upper-level trough. Additional analyses demonstrate that, compared to corresponding null cases, Rossby wave breaking cases resulting in widespread EPEs exhibit a significantly higher-amplitude wave pattern that favors greater poleward transport of moist, conditionally unstable air and stronger ascent over the EPE region.

scholarly journals Transport of Antarctic stratospheric strongly dehydrated air into the troposphere observed during the HALO-ESMVal campaign 2012

2015 ◽  
Vol 15 (16) ◽  
pp. 9143-9158 ◽  
Author(s):  
C. Rolf ◽  
A. Afchine ◽  
H. Bozem ◽  
B. Buchholz ◽  
V. Ebert ◽  
...  
Keyword(s):  
Water Vapor ◽  
Rossby Wave ◽  
Wave Breaking ◽  
Trajectory Analysis ◽  
Exchange Process ◽  
Near Surface ◽  
Air Masses ◽  
Rossby Wave Breaking ◽  
The Antarctic

Abstract. Dehydration in the Antarctic winter stratosphere is a well-known phenomenon that is annually observed by satellites and occasionally observed by balloon-borne measurements. However, in situ measurements of dehydrated air masses in the Antarctic vortex are very rare. Here, we present detailed observations with the in situ and GLORIA remote sensing instrument payload aboard the German aircraft HALO. Strongly dehydrated air masses down to 1.6 ppmv of water vapor were observed as far north as 47° S in an altitude between 12 and 13 km in the lowermost stratosphere. The dehydration can be traced back to individual ice formation events above the Antarctic Peninsula and Plateau, where ice crystals sedimented out and water vapor was irreversibly removed. Within these dehydrated stratospheric air masses, filaments of moister air reaching down to the tropopause are detected with the high-resolution limb sounder, GLORIA. Furthermore, dehydrated air masses are observed with GLORIA in the Antarctic lowermost stratosphere down to 7 km. With the help of a backward trajectory analysis, a midlatitude origin of the moist filaments in the vortex can be identified, while the dry air masses down to 7 km have stratospheric origins. Antarctic stratosphere–troposphere exchange (STE) and transport of dehydrated air masses into the troposphere are investigated. Further, it is shown that the exchange process can be attributed to several successive Rossby wave events in combination with an isentropic exchange of air masses across the thermal tropopause. The transport into the troposphere is caused by air masses that are detached from the potential vorticity (PV) structure by Rossby wave breaking events and subsequently transported diabatically across the dynamical tropopause. Once transported to the troposphere, air masses with stratospheric origin can reach near-surface levels within several days.

An American Language

2018 ◽  
Author(s):  
Rosina Lozano
Keyword(s):  
United States ◽  
National Policy ◽  
The United States ◽  
Spanish Language ◽  
Spanish Speakers ◽  
Language Recognition ◽  
Political Language ◽  
Political Issue ◽  
History Of ◽  
The U.S

An American Language is a political history of the Spanish language in the United States. The nation has always been multilingual and the Spanish language in particular has remained as an important political issue into the present. After the U.S.-Mexican War, the Spanish language became a language of politics as Spanish speakers in the U.S. Southwest used it to build territorial and state governments. In the twentieth century, Spanish became a political language where speakers and those opposed to its use clashed over what Spanish's presence in the United States meant. This book recovers this story by using evidence that includes Spanish language newspapers, letters, state and territorial session laws, and federal archives to profile the struggle and resilience of Spanish speakers who advocated for their language rights as U.S. citizens. Comparing Spanish as a language of politics and as a political language across the Southwest and noncontiguous territories provides an opportunity to measure shifts in allegiance to the nation and exposes differing forms of nationalism. Language concessions and continued use of Spanish is a measure of power. Official language recognition by federal or state officials validates Spanish speakers' claims to US citizenship. The long history of policies relating to language in the United States provides a way to measure how U.S. visions of itself have shifted due to continuous migration from Latin America. Spanish-speaking U.S. citizens are crucial arbiters of Spanish language politics and their successes have broader implications on national policy and our understanding of Americans.

Palestine Unbound

2018 ◽  
Vol 47 (3) ◽  
pp. 130-134
Keyword(s):  
United States ◽  
Human Rights ◽  
Task Force ◽  
The United States ◽  
Donald Trump ◽  
Tel Aviv ◽  
The Us ◽  
Intention To Move ◽  
Arab Israeli Conflict ◽  
The U.S

This section, updated regularly on the blog Palestine Square, covers popular conversations related to the Palestinians and the Arab-Israeli conflict during the quarter 16 November 2017 to 15 February 2018: #JerusalemIstheCapitalofPalestine went viral after U.S. president Donald Trump recognized Jerusalem as the capital of Israel and announced his intention to move the U.S. embassy there from Tel Aviv. The arrest of Palestinian teenager Ahed Tamimi for slapping an Israeli soldier also prompted a viral campaign under the hashtag #FreeAhed. A smaller campaign protested the exclusion of Palestinian human rights from the agenda of the annual Creating Change conference organized by the US-based National LGBTQ Task Force in Washington. And, UNRWA publicized its emergency funding appeal, following the decision of the United States to slash funding to the organization, with the hashtag #DignityIsPriceless.

The French Way

2011 ◽  
Author(s):  
Richard F. Kuisel
Keyword(s):  
United States ◽  
The United States ◽  
French Language ◽  
French Cinema ◽  
Free Markets ◽  
Technology Sector ◽  
Aids Epidemic ◽  
Political Reality ◽  
Politics And Culture ◽  
The U.S

There are over 1,000 McDonald's on French soil. Two Disney theme parks have opened near Paris in the last two decades. And American-inspired vocabulary such as “le weekend” has been absorbed into the French language. But as former French president Jacques Chirac put it: “The U.S. finds France unbearably pretentious. And we find the U.S. unbearably hegemonic.” Are the French fascinated or threatened by America? They Americanize yet are notorious for expressions of anti-Americanism. From McDonald's and Coca-Cola to free markets and foreign policy, this book looks closely at the conflicts and contradictions of France's relationship to American politics and culture. The book shows how the French have used America as both yardstick and foil to measure their own distinct national identity. France has charted its own path: it has welcomed America's products but rejected American policies; assailed Americ's “jungle capitalism” while liberalizing its own economy; attacked “Reaganomics” while defending French social security; and protected French cinema, television, food, and language even while ingesting American pop culture. The book examines France's role as an independent ally of the United States, but he also considers the country's failures in influencing the Reagan, Bush, and Clinton administrations. Whether investigating France's successful information technology sector or its spurning of American expertise during the AIDS epidemic, the book asks if this insistence on a French way represents a growing distance between Europe and the United States or a reaction to American globalization. Exploring cultural trends, values, public opinion, and political reality, this book delves into the complex relationship between two modern nations.

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